1. Field of the Invention
This invention relates to agricultural harvesting equipment in general, and more precisely to a self-contained friction reducing slip member provided for shaker heads of nut and fruit tree-shaker equipment.
2. Description of the Prior Art
In my earlier U.S. Pat. No. 4,921,073 entitled METHOD AND APPARATUS FOR LUBRICATING THE SHAKER HEADS OF A TREE SHAKING HARVESTER, issued May 1, 1990, I teach a method and structure of effectively lubricating the shaker heads of shaker type nut and fruit tree harvesting equipment. The shaker "head" is the padding or pad layer or pad layers affixed on the distal end of the shaker arm in order to cushion between the steel arm end and the tree. The primary object of the padding of conventional shaker heads is to prevent damage and injury to the trees when the two opposing shaker heads are clamped on either side of the tree and vibrated to dislodge the nuts or fruit. Each of the two shaker heads of the harvesting machine normally includes a large cylindrical resilient main pad which is attached to the distal ends of the metal shaker arms by a flat rectangular retaining sling, the sling generally comprised of a rubberized material which is wrapped over the pad and the ends of the sling affixed to the metal shaker arm with bolts or other suitable clamping or affixing arrangements. The main pad is made of thick and quite stiff rubbery material which is flexible, but the degree of flexibility is very low in that it is structured to compress and flex under the high clamping pressures of the opposing shakers arms. The shaker arms are most often arranged to clamp against a tree with the clamping pressure being applied by hydraulic rams on the shaker arms, and thus the clamping pressure is high per square inch. Normally a second flat rectangular member, the slip pad, is placed over the exterior of the sling and is structured to remain stationary against the tree when in use due to lubricant being placed between the sling and the slip pad. By remaining stationary against the tree, the slip pad protects the bark and cambium layer of the tree from being frictionally rubbed off, or in effect sanded off by the violent vibratory effect produced by the shaker heads, which could otherwise strip the bark and cambium layer and kill the tree. Placing lubrication between the slip pad and the retaining sling of the shaker head helps reduce friction and allows movement between the two, with the outer slip pad remaining stationary against the tree with the high clamping pressure of the opposing shaker arms. Shock waves are carried from the moving shaker arm and pad and sling through the stationary slip pad to impact the tree and thus cause shaking and vibration in the tree limbs sufficient to dislodge all of the nuts or fruit. The lubricant also increases the life span of the component parts of the shaker heads by reducing friction and thus heat, with heat being a major cause of the break-down of the padding of the shaker head.
The old method of lubricating the heads, prior to the introduction of my prior invention of U.S. Pat. No. 4,921,073, required manual application of the lubricant. This involved periodic stopping of the harvester to reapply the lubricant which entailed unhooking one end of the slip pad, raising it up away from the retaining sling, and placing the lubricant on the sling with a brush. This manual application of lubricant resulted in greatly increasing the harvesting time since the operator had to make a concerted effort to remember to apply the grease at the appropriate time which was normally several times an hour.
My prior invention taught in U.S. Pat. No. 4,921,073, includes a lubricant filled reservoir attached to a pressuring device which is used to deliver lubricant from the reservoir through a hose to the space between the padding and slip layers of the shaker heads. Because of the similar features of my previous invention to my present invention, my U.S. Pat. No. 4,921,073 is herein incorporated by reference.
While the method and apparatus for lubricating shaker heads as taught in my previously mentioned U.S. patent works well, the lubricant is not fully contained, but is disbursed and eventually lost out the ends and bottom of the shaker heads, which requires periodic replenishment of the lubricant. Compared to the present invention of this disclosure, this periodic reapplication of lubricant increases operating costs since extra lubricant must be purchased and extra time must be taken to refill the lubricant reservoir at the beginning or end of each operating day. An even more significant disadvantage of all related prior art involves the discharged or discarded lubricant. Today, there is an increasing awareness of potential environmental pollutants, and stricter regulations are being placed on agricultural practices. There is a perceived potential danger from the discarded lubricant accumulating in the soil to the point where some type of hazardous residue may show up in the harvested fruit, or that the lubricant may seep into underground water supplies or simply end up in streams and lakes with rain runoff. Therefore, there is a significant need to provide a fully contained lubrication system for the shaker heads of fruit tree harvesting equipment.